Rubble from war-torn buildings repurposed as concrete aggregate

Concrete aggregate made from the rubble of buildings destroyed by war in Syria can be used as an alternative to the raw materials in concrete, researchers have found.

Buildings destroyed by war in Aleppo, Syria
Buildings destroyed by war in Aleppo, Syria - AdobeStock/Fly and Dive

Led by Dr Theodore Hanein and Professor John Provis from Sheffield University’s Department of Materials Science and Engineering, the study has proven for the first time that recycled concrete aggregate can be used as a sustainable alternative to the raw materials in concrete.

The research shows that the rubble could replace up to 50 per cent of the raw materials used in concrete without significantly affecting its performance. The team’s research is detailed in the Journal of Materials in Civil Engineering.

In a statement, Dr Theodore Hanein, UKRI Future Leaders Fellow at Sheffield University, said: “Sadly, the ongoing civil war in Syria has left more than 130,000 buildings destroyed, and now after the devastating earthquake even more buildings have been damaged or destroyed in northern parts of the country.

“For the past four years we’ve been working with Syrian academics to find ways of reusing the vast amount of rubble that has been left behind by the war and we have now found a way to recycle it that could help the country recover once it comes to the time of rebuilding.” 

Dr Hanein continued: “One of the big barriers to reusing materials to make new concrete is determining whether the final product will be as strong and reliable as concrete produced in the traditional way. Our paper shows how this can be done in Syria, with the potential to replicate this work around the world.”

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The work began when a group of Sheffield researchers wanted to help exiled Syrian academics fleeing the civil war. The Sheffield researchers used their expertise in sustainable engineering, in collaboration with experts from the Department of Civil and Structural Engineering and from Middle East Technical University (METU), Turkey, to coordinate studies investigating the reuse of rubble being left behind by the conflict to help rebuild the country. 

The Syrian academics visited Sheffield University in 2019 to perform experiments, and the study has since been developed in Sheffield and at METU. The Syrian academics are conducting the research with support from the Cara (Council for At-Risk Academics) Syria Programme. 

Making concrete from rubble is not a new idea, but the team in Sheffield said this is the first time that a proven technique has been developed for buildings destroyed in war. As each country uses different materials to construct buildings, the properties of any new concrete produced using recycled rubble must be thoroughly assessed to ensure they meet the standards required for safe and reliable construction.

“Cara is most grateful to this amazing group of researchers from Sheffield and METU, who have given their time to help guide and support this incredibly important work in the context of Syria,” said Kate Robertson, Cara Middle East/Syria programme adviser. “It is envisaged that using these methods to help rebuild Syria could create the foundation for it to become a technological hub for green and circular materials and construction solutions in the region into the future.”